This invention relates to an apparatus for transferring a tread ring which is used in a green tire building system.
In green tire building systems, a tread ring is built on a tread ring forming drum, and then transferred from the tread ring forming drum to around carcass plies placed on a tire building drum by a transferring apparatus.
FIG. 8 shows a principal portion of a typical conventional transferring apparatus. The conventional transferring apparatus includes a holder frame 100 in the form of ring and a number of holding segments 101 provided inside the ring-shaved holder frame 100. The holder frame 100 is reciprocally moved from the tread ring forming drum to the tire building drum, and vice versa. Each holding segment 101 has a rectangular contact member 102 on an inner end thereof. The contact members 102 are arranged in a circumferential direction at the same interval. The contact members 102 are moved in radial directions of the ring-shaped holder frame 100. The contact members 102 are simultaneously moved in inner directions to hold the tread ring T while moved in outer directions to release the holding of the tread ring T.
In tires produced with use of the conventional transferring apparatus provided with the contact members 102 arranged at the same interval, however, there have been noticeable Radial Force Variations (referred to as "RFV" hereinafter) in the high variation modes.
It will be seen that vibrations caused by RFVs in the high variation modes are liable to resonate with vibrations of particular members of an automotive vehicle running at high speeds, and generate undesirable noises. Accordingly, there have been demands of reducing the RFV in the high variation modes as low as possible.